This invention relates to parts-handling apparatus for aligning and feeding elongated objects to be tested or to be conveyed to an assembly machine for assembly on printed circuit boards.
Assembly machines are used to automatically assemble an article from its component parts. Injector razors, spark plugs, and light bulbs are but a few of the types of articles typically assembled by assembly machines. Sophisticated electronic devices containing electronic components such as diodes, resistors, capacitors and the like may also be assembled by assembly machines. The assembly machines may be of the "rotary" type, such as disclosed in U.S. Pat. Nos. 3,065,530 and 3,231,968, assigned to the assignee of the present invention, or of the "in-line" type, such as disclosed in U.S. Pat. Nos. 2,887,209 and 2,990,940, also assigned to the assignee of the present invention.
Electronic components such as diodes, resistors, and capacitors may be of the type having an elongated cylindrical body with a wire lead at either end of the body. A typical banded resistor, for instance, has this elongated configuration. When large numbers, of these electronic components are supplied for assembly, such as into printed circuit boards, they may be packaged in bulk so that the wire leads of the components can become bent or tangled. While such bulk quantities of these electronic components can be manually sorted, aligned, and sequentially fed, it is often necessary and desirable to accomplish sorting, alignment, and feeding by machine. When these components are sequentially fed to a conveying apparatus, they can then be attached in a continuous row on tape strips for storage for later use, or they can be fed directly to machines for further assembly.
Prior attempts to sort, align, and sequentially feed elongated objects such as electronic components by machine have not always been successful in accommodating parts with bent leads. It has been found that, for instance, elongated objects having a central cylindrical body and a wire lead at each end can be used by automatic assembly machines for certain applications even though the leads may be bent at angles as great as 60.degree. from the axis of the cylindrical body. However, known apparatus for accomplishing sorting, alignment, and feeding of such objects have generally not been able to feed parts having leads bent at an angle so great that they extend above the axis of the body a distance greater than the body's radius. For instance, although vibratory bowls and feeders have been used to attempt to feed such elongated objects, known apparatus have not been successful in arranging such elongated objects transversely for sequential feeding so that the cylindrical walls of the components are adjacent one another, when the elongated objects have leads bent a distance greater than the radius of the cylindrical body.
The disadvantages in the feeding obtained by the machines of the prior art have increased the amount of manual sorting required for sequential feeding of such elongated objects. Bent leads on the objects tend to jam the feeders of the prior art, which may be in the form of zig-zag gravity feeders, requiring manual removal from the feeder. If bent leads are rejected by the known apparatus, such as into the bottom of the vibratory bowl, they must be manually removed. High feed rates are desirable in such machines, but known apparatus have typically been limited to rates of about 60 to 70 per minute, and manual removal of objects with bent leads decreases the effective feed rate even further.
Accordingly, the present invention overcomes disadvantages of the known apparatus by providing an apparatus and method that can accommodate and feed elongated objects having bent leads, at least up to about 60.degree.. The apparatus of the present invention is less susceptible to jams than known apparatus, and also provides mechanical disentanglement of the elongated objects so that it can better accommodate elongated parts fed in bulk. The apparatus of the present invention also has a feed rate of at least about 200 parts per minute, thus presenting a significant improvement over known apparatus. In short, the present invention provides sorting, aligning, conveying and feeding of elongated parts such as electronic components with simple and economical operation, versatility, and reliability in use. Other objects and advantages of the present invention will become apparent as the description of the invention proceeds.
Briefly, in accordance with the present invention, there is provided an apparatus for aligning and sequentially feeding elongated objects or parts including a vibrating bowl for receiving the elongated objects, a means positioned within the bowl for removing bent objects and limiting the number of elongated objects conveyed up the bowl in side-by-side relationship, and means for feeding the elongated objects sequentially from the top of the bowl. The bowl has a base, a side wall, and a ramp spiralling along the inner perimeter of its side wall so that when the bowl is vibrated the elongated objects pass along the upper surface of the ramp from the bottom end of the ramp adjacent the base portion to the top end of the ramp.
According to the preferred embodiment of the present invention, the means for removing bent objects and limiting the number of elongated objects is a plurality of sorting stations defined by areas of smaller ramp widths. Inclines are provided in connection with the areas to permit the elongated objects to roll away from the ramp surface back to the next lower ramp level or all the way to the base of the bowl. A hopper and trough arrangement are provided near the bowl to feed a supply of elongated objects into the bowl at a controlled rate. Photoelectric means are also provided for sensing the quantity of elongated objects in the bowl and for controlling the rate at which the hopper supplies elongated objects to the bowl.
In order to disentangle clumps of elongated objects in bulk, the hopper includes a plurality of horizontal bars positioned across its bottom and at least one slanted bar angling upwardly from the horizontal bars to the front or leading wall of the hopper. Positioned adjacent the output end of the bowl, that is, at the uppermost end of the ramp, are a first slide and an adjacent curved second slide, together comprising the means for feeding the elongated objects sequentially. The first slide is inclined so as to direct each object approximately perpendicular to its axis and the curved slide is positioned to receive the elongated objects as they exit the first slide so that their downward motion continues but their lateral direction of motion is changed. Adjacent the output edge of the curved second slide is a rotating pick-up apparatus for removing the elongated objects sequentially from the second slide. This rotating pick-up apparatus is preferably a spur gear driven by a motor.
While the invention will be described in connection with preferred embodiments, it will be understood that it is not intended to limit the invention thereto, but rather to cover all modifications and alternative constructions falling within the spirit and scope of the invention as broadly defined. The invention will be further described in conjunction with the appended drawings.